1. Field of the Invention
This invention relates to a collar attached to the side of a manhole to protect an outside drop adjacent the manhole, and alternatively for the plurality of collars to form a protected outside drop.
2. Description of the Related Art
When an outside drop is used adjacent a manhole the outside drop is subject to damage and subsequent leaks by rocks and other fill material and due to shifting of the ground, the weight of the pipes and other factors. It is desired to have a protective collar around the drop pipe.
Currently protective collars are very heavy which makes them difficult and expensive to transport and install. The protective collars in use need to be set on a solid base as part of the base of the manhole, which makes the manhole itself heavier, more expensive and more difficult to install in the ground. The collars surround a drop pipe must be made the correct size to support the drop pipe, collars and connections, particularly at the top of the outside drop where there is a T connection and at the bottom of the outside drop where there is an elbow pipe connection. Since riser collars are made of concrete they are very heavy and require tools to lift the collar parts into place. Since the riser collars are not fastened to the manhole they may have gaps between the manhole and the collar or may shift way from the manhole.
Outside drop pipes are generally made from ductile iron, which is heavy, expensive and hard to work with. Plastic pipe is lighter, costs less, is easier to connect and easier to work with. However plastic pipe is more subject to damage and needs protection.
A lightweight easy to install protective collar is attached to the side of a manhole to surround an outside drop while securing the outside drop in place adjacent the manhole. The protective collar can be one or more sections separated by some distance or the sections can be stacked to form a continuous protective barrier. The collar can form around an outside drop pipe or the collars can have an opening therein to form the outside drop pipe inside the collar. The diameters of the pipes on the outside drop can be standardized by using expansion or reduction pipes at the top or bottom of the manhole so that only one size protective collar needs to be used. Similarly with a combination internal pipe and collar only one size internal pipe needs to be produced when expansion and contraction collar sections are used. The collars can fit over expansion or reduction pipes and over elbow pipes. The collars with integral pipes can fit around expansion or reduction internal pipes and elbow pipes, and can have expanded portions for fitting over pipe coupling segments and flanges. The collars for fitting over pipes can be split radially or perpendicular to radially and assembled around the pipes. The collars for fitting over pipes can have expanded portions for fitting over pipe coupling segments and flanges.
Tubes molded into collars and extending between opposing walls add strength to the collars, which are molded as hollow parts. To add weight and stability an aperture in the top of the collars can be used to fill the collars with sand or other material to increase the weight and impact absorbing ability of the collars. Similarly apertures in the sides of the collars can let water in if the water table rises and let water out when the water table declines.
It is an object of the invention to provide a lightweight outside drop collar.
It is an object of the invention to provide an easy to assemble outside drop collar.
It is an object of the invention to provide a low cost outside drop collar.
It is an object of the invention to provide an outside drop collar that attaches to a manhole.
It is an object of the invention to provide an outside drop collar that does not need a base on the manhole.
It is an object of the invention to provide a combination collar and outside drop pipe for a manhole.
It is an object of the invention to provide size adaptors for connecting pipe to the outside drop to standardize the size of the outside drop collar sections.
It is an object of the invention to provide collar sections in standard heights to fit manhole heights.
It is an object of the invention to provide an outside drop collar with apertures for letting water in or out of the collar.
It is an object of the invention to provide an outside drop, which can be filled to add weight and strength to the outside drop collar.